WaterFurnace Boasts State-of-the-Art Facility
Courtesy of WaterFurnace International
Explosive sales and a quest for a state-of-the-art facility led WaterFurnace International, Inc. to
build a new 115,000 square-foot corporate headquarters and manufacturing facility in Fort
Wayne, Ind. In conjunction with the new building, WaterFurnace installed the largest
GeoExchange water loop system in North America to provide heating and cooling for the
building.
To provide total comfort for the new headquarters and plant, WaterFurnace used a combination
of its own GeoExchange units, including the Premier AT and Spectra units. The system consists
of horizontal units conditioning various zones within the two-story office space and seven large
capacity horizontal units that total 150 tons conditioning the manufacturing area. The
environmental control for the testing laboratory consists of 42 Premier units. The 168 tons of lab
support equipment uses the pond loop as a tempering medium when lab requirements fluctuate
outside of specified limits.
Pond Loop Installation
Due to city zoning ordinances, WaterFurnace constructed a retention pond for storm water runoff.
WaterFurnace saw this as a great opportunity to combine a beautiful focal point with a costeffective water loop installation. A three-acre pond dominates the front of the facility which
overlooks a major thoroughfare.
The water loop system consists of 12 heat exchanger zones spread over the bottom of the eight
foot-deep pond. Each zone is constructed from fifteen 300 foot-long coils of 3/4-inch thermoplastic pipe connected with the building by two-inch supply and return lines. The high-density
polyethylene piping used for the loop is joined by a heat fusion process that forms an
unbreakable connection stronger than the pipe itself. A water loop system was the most costeffective method for WaterFurnace to install a GeoExchange system. By utilizing the retention
pond, WaterFurnace saved a considerable amount of money that would have been spent to
excavate a vertical or horizontal loop. The pond is also used as a source of water for the lawn
sprinkler system.
During the first summer of operation, the maximum water loop temperature returning from the
pond was 85 degrees Fahrenheit (F) during periods of 100 degrees F and higher outdoor air
temperatures. In these conditions, the WaterFurnace Premier units cool with an energy efficiency
ratio (EER) of 16, which is about double that of conventional cooling.
During the winter when the pond is frozen at the surface, water loop temperatures are a minimum
of 35 degrees F. Under these conditions, Premier units heat with a coefficient of performance
(COP) of 4. This is four times more efficient than electric resistance heating and provides
considerable savings when compared to the highest efficiency gas systems.
Setting the Standard
WaterFurnace’s office and manufacturing facility is a model application from which architects and
engineers can learn. The facility is a working model of a water loop installation for large-scale
commercial and industrial buildings, many of which currently require retention ponds.
Energy Management System
All space conditioning and lighting is controlled by a highly advanced Energy Management
System (EMS), converting the structure into an "intelligent building." Intelligent building control
substantially reduces operating costs while providing higher levels of safety, comfort and
convenience for the occupants. The EMS gives complete computer control over connected
devices as well as providing communication between devices.
Direct Digital Controllers
The EMS consists of an interconnected network of Direct Digital Controllers (DDC). Each
controller regulates a local system or device according to its own program or programs from
central commands. Each GeoExchange unit has one controller, allowing sophisticated control
over heating and cooling algorithms and schemes. A simple example is the scheduling program
that automatically sets back heating and cooling set points during unoccupied times such as
nighttime, weekends, or holidays.
At each GeoExchange unit, the EMS monitors conditions such as space temperature, air intake
temperature, air discharge temperature, fault conditions, and occupant thermostat commands.
Each controller analyzes these inputs, then controls the unit through the proper heating and
cooling sequences to ensure a comfortable environment at maximum efficiency.
Each DDC controller is fully programmable over a LAN (local area network), thus individual
controls throughout the entire building can be programmed from one central laptop computer
which can be located anywhere in the building. Each controller can be programmed to
communicate with other controllers and can share data dynamically with other controllers. Two
touch-screen displays, which provide information and graphic interaction with occupants, are
located in the facility. Users may check the status and conditions anywhere on the EMS and with
proper password authorization can alter system schedules, set points, and even individual control
programming.
The EMS also monitors and controls the variable-speed water loop pumping system. Each unit
was fitted with an actuator water valve that allows water flow only when required. Since the loop
water flow fluctuates based on the number of units operating, the EMS determines the speed at
which the variable-speed pumps must operate, thus minimizing pumping costs.
Because electricity costs are based to a large extent upon maximum electric demand, the EMS
monitors information at the main electric meter. When high demand periods arise, the EMS
schedules off low priority loads. This feature minimizes utility loads during peak periods and
saves substantially on utility costs.
System Design
WaterFurnace located the units and designed the air duct systems by dividing the building into
zones, grouping similar usage areas together. For example, several offices facing the same
direction and having similar heating and cooling needs are handled by one unit. Breaking the
building into zones with similar requirements provides better comfort than large central systems
where all areas are governed by one thermostat.
Horizontal units were used throughout the facility to maximize usable floor space. The units are
located above the suspended ceiling in an otherwise unused space, which also serves as the
return air plenum. This eliminates the need for expensive return air ductwork. A percentage of
fresh outside air is ducted directly to each unit to provide a healthy indoor environment. A heat
recovery system was installed to recover the energy from exhaust air such as in restrooms. This
energy is used to condition the incoming fresh air providing for high energy efficiency.
To maximize the pond view, a continuous ribbon of glass surrounds the perimeter of the building
throughout the office and manufacturing areas. When faced with large amounts of glazed areas,
many engineers install perimeter radiation for heating. This is expensive to install and to operate.
With GeoExchange units, the supply air temperatures are high enough that ceiling mounted linear
slot air diffusers can be used to blanket the perimeter wall with warm air for high comfort at low
installation and operation costs.
The main lobby, designed with two-story glass walls, presented a challenge for lower level
comfort. For this unique situation, a Premier AT downflow unit was installed to condition this
space. The ductwork was located within the floor slab so the supply air could be introduced at
floor level where the occupants are located.
The 24-foot high manufacturing area utilizes a stratified air concept to minimize cooling loads. In
summer, the units are ducted to condition only the lower ten feet of the space. This allows the
massive amounts of heat gain from the roof and overhead lighting to remain near the ceiling
where it does not require conditioning. During the winter, this upper level air is used to assist in
heating. By utilizing a stratified air system, only 70 tons of cooling is required in the 85,000
square-foot area. With a conventional rooftop system, a space this size would typically require
200 tons of cooling.
Great Savings
The WaterFurnace facility demonstrates to architects and engineers how state-of-the-art
GeoExchange technology can be successfully applied to their projects. Installation costs for a
GeoExchange water loop system can be surprisingly lower than many conventional systems. And
tremendous comfort and operating cost benefits can be achieved.
Facility
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Square Footage: 115,000
Type of System: Pond Loop
Number of Units: 41
Total Capacity (HVAC Ton): 153
Location
The WaterFurnace Facility is located in Fort Wayne, Indiana.
Contact Information
WaterFurnace International
Mr. Bill Dean
9000 Conservation Way
Fort Wayne, IN 46809
Tel. 219-478-5667
Tel. 800-222-5667
Fax 219-747-2828
E-mail: bill_dean@waterfurnace.com
Taken with permission from the US Geothermal Heat Pump Consortium, http://www.geoexchange.org. Copyright reserved.